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MG MGF Technical - Episode 2 Front Fog switch Mk1 to Mk 2 conversion

Hello everyone,

Returned from my trip abroad to find not a single response to my dilema, are there so few people out there with MK2 front fogs fitted or is it just too cold too look under the console at present.

Well from the warmth of my living room I have just been browsing Moss's new catalogue and noticed the TF Fog loom only has four wires, 2 red & 2 black, red wired to pins 1&2 and black to pins 4 & 5 could this be the answer I have been looking for.

The loom is obviously wired completely differently from Mk1 to Mk2, again I would appreciate it if anyone who has this set up can confirm this.

The new Moss catalogue has some nice gadgets in it, chrome and anodised gear bezel surrounds, lighter covers, heater dial trims, dash trims, sports headgasket which claims to beat the HGF problem. Worth ordering a copy I think.

In addition, flaming hand brake has seized whilst I have been away, anyone have any tips for freeing up the hand brake.

There, 3 for the price of one, can anyone beat Rob to a reply.


Chris Catchpole

>In addition, flaming hand brake has seized whilst I
>have been away, anyone have any tips for freeing up the
>hand brake.
Put car in gear and be careful with the cluch
Will Munns

>> Well from the warmth of my living room I have just been browsing Moss's new catalogue and noticed the TF Fog loom only has four wires, 2 red & 2 black, red wired to pins 1&2 and black to pins 4 & 5 could this be the answer I have been looking for. <<

Is this Moss' kit an MG kit but re-branded, or one that they've put together themselves? If the latter, then the wiring they use may not be applicable for you Chris - but it is worth a go!
Rob Bell

Yes almost right Chris, just looked at my TF

1 red/black
2 red/black
3 spare
4 red and orange
5 black

let me know if you need more

John Thomas

Thanks John, I appreciate you taking the time to look for me. It looks like your connector is wired the same as the one in the Moss catalogue but has different coloured wires. Mine (Mk1 loom) has 5 wires so I need to work out which is active with the new switch.

Rob if you read this does the pic John has sent shed any light on the matter.

Thanks again John, I now can work from this to try to get the switch working correctly. Can you see through the bumper grille to see which wires go to the fog lamps themselves.
Chris Catchpole

The hand brake hasn't seized on it is seized off, if that makes sense.

Not coming on at all, so rolling down hill. It passed MOT 3 weeks ago so must have been fine then. Is there anything I should be looking for. The handbrake handle feels lose, it is sprung upwards slightly in its resting position, I can push it down with my finger about 2 cm and it has about 3cm play in the upwards direction before any tension is felt.

Could it be siezed at the caliper. Rear brakes appear to be working fine as disks are clean on both sides and I would suspect rust would have formed on the disks by now if the brakes weren't working.

Handbrake warnning light is on but this appears to be because the handbrake is resting off the microswitch, push down on the handle and the light goes off.
Chris Catchpole

Chris, I guess that this does make some sense - and is certainly worth a go!

Obviously, the TF uses a different circuit set up to the MGF - at least with the switch that you've got. [I wonder whether some of the confusion may be down to the fact that MGR have altered the TF wiring system recently - new TFs use a different immobiliser unit and fuse board - and possibly also a different multi-function unit! A quick check of the EPC should help clarify this question]

R/B is the instrument illumination circuit, so presumably this live will engerise the front fog relay (as opposed to the feed from the MFU). 5 is used as the common ground...

Chris, you posted this information regarding the switch:
In the On position:
Pins 1 + 4 have full resistance, make circuit
Pins 1 + 5 have full resistance, make circuit
Pins 4 + 5 have full resistance, make circuit
Pins 1 + 3 have slight resistance with reverse polarity pin 1 -ve pin 3 +ve
Pins 1 + 5 have slight resistance with reverse polarity Pin 1 -ve pin 5 +ve
Pins 3 + 4 have slight resistance both ways
Pins 3 + 5 have full resistance, make circuit

So, from JT's car we see that
1 red/black
2 red/black
3 spare
4 red and orange
5 black

Looking at the pix of your disassembled switch (, it appears that 1&5 are the switched ground for the fog lamp relay, the red/orange on pin 4 grounds through pin 5 and pin 2 is the instrument illumination.

Therefore, I'd wire your switch as follows:
1. Black/Slate grey
2. Red/Black
3. Spare
4. Red/Orange
5. Black

Fingers crossed Chris! :o)
Rob Bell

Almost there Rob.

The set up you mentioned has everything working but also has an high pitched whistling noise coming from below the dash, similar too but not the same as lights on warning alarm when the door is open. This noise is continuous and is there with the door open or closed.

Remove the black wire and it goes away but the fogs then go out. Could the relay be making the noise?

Swapping over BS with RB also has the same effect.

So I am left with 2 black wires and pin 3 and 5 vacant, illumination and on/off lights working but no fogs.

I will keep trying because i am sure we are close now.
Chris Catchpole

Okay, not sure why you are getting a high pitch whilstle - but I'd suspect that this is a problem with current flow to the MFU! :o(

What happens when you disconnect only pin 1 and have the black reconnected to pin 5? Same noise?

My only other suggestion is to keep the red/black on pin 2, but consider swapping the Red/Orange and Black/Slate wires to pins 1 and 4 respectively...

I agree with you Chris - I think that we're very nearly there... :o)
Rob Bell

Hi Rob,

I have had the lights on without the noise but then I do not get illumination of the switch, I hope we can crack this and then post the results for other BBS users benefit.

I really appreciate your help with this. I will try some more cable swapping this evening and post my findings.

Chris Catchpole

Rob, the high pitch whistle noise is coming from the relay.

Pin 1 BS + Pin 4 BK alone work the lights fine without noise.

Pin 1 BS + Pin 2 RB and Pin 5 BK alone gives illumination of switch when stem on and on/off illumination works too but no fogs.

Pin 1 BS, Pin 2 RB, Pin 4 BK, & Pin 5 RO together gives illumination with headlight stem selection but when the fog switch is selected to On the illumination goes out but the fog lights do come on with no relay noise. There is no On indication/illumination on the switch either.

So I can have the fogs on which is indicated by the fact the switch illumination goes out, LOL, not quite right yet.

With the volt metre when the fog switch is in the Off position and dash illumination is on through headlamp stem I have 12V across Pin 1 & 4 and 1 & 5.

In the On position I get 12V across pins 1 & 2 but with reverse polarity and 1 & 5 again in reverse polarity.

I have a headache again now and need to lie down in a dark room.
Chris Catchpole

Why on earth would the relay be making that noise then??? :o(

I am pretty sure that pin5 is the common earth. Pin 4 is the live wire from the fogs that grounds through pin 5, but is only live when the fog relay is energised through completing circuit from pin 1 to pin 5.

SO why is the relay making noise? The way it was wired, with 1=BS, 2=RB, 3=spare, 4=RO and 5=B should all work????

Yup, definitely time to attack the anadin...
Rob Bell

Chris, just been interogating the switch you've sent me.

Pins 3&5 are always live.

Pins 1&4 are switched.

The tricky bit is understanding the circuit through the light emitting diodes - this may require a little more thought! At the moment, I am thinking that we need to swap the RO wire on pin 5 with the B wire on pin 4... leaving Pin 1 BS and Pin 2 RB
Rob Bell

Hi Chris - sorry, only just found this site & registered! If it's any help RE slack in the handbrake, prising out the cubby box & slightly tightening the adjusting nut on the compensator attached to the handbrake lever sorts the seemingly common prob. of it springing up & activating the warning lamp...e-mail me if you want further details/photos.
ps wouldn't happen to be in Durham MGOC by chance??? I know some do come from Teeside & I'm in Darlington...
Dave Smithson

This thread was discussed between 24/02/2004 and 04/03/2004

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